In the case of a known latching mechanism for a spring-powered drive, in which the associated spring energy store is tensioned by use of a rotary drive and an extensible toggle lever system, the extensible toggle lever system is locked with the spring energy store under tension by a support element, an auxiliary lock and a primary lock in addition to a stop allocated to the primary lock. In the case of this latching mechanism, in which the supporting element designed as a lever is articulated on the one hand on the toggle joint of the toggle lever system and on the other hand on the auxiliary lock, the auxiliary lock can be pivoted by extension of the lever system.
In this case, the auxiliary lock and the primary lock have working surfaces allocated to one another, by which the position of the primary lock during the pivoting of the auxiliary lock can be influenced (DE 44 16 088 C1). In this case, a first working surface of the auxiliary lock is formed by a semicircular portion of the peripheral edge of the auxiliary lock which lies adjacent to a working surface of the primary lock designed as a roller, and keeps the primary lock in a first position counter to the force of the return spring allocated to it. In this first position, a half-shaft forming the stop is locked by the primary lock under spring pretension.
A second working surface, which is designed as a set-back edge and is likewise allocated to the roller, releases the primary lock at the end of the tensioning operation, so that on the one hand the primary lock pivots under the force of the return spring allocated to it in overtravel behind the half-shaft. On the other hand, the released half-shaft pivots on account of its spring pretension into the path of movement of the primary lock. Both pivoting operations must proceed before the primary lock pivots in the reverse direction by decoupling of the lever system from the rotary drive under the effect of the force of the spring energy store.
Since an indicating element for the state of the spring energy store is usually coupled to the primary lock, it is at the same time expedient with regard to the certainty of the indication that the primary lock pivots in overtravel behind the half-shaft only shortly before the decoupling of the lever system from the rotary drive. For this purpose, rapid movements of the latching mechanism are required, in particular when there is a high energy content of the spring energy store. In the case of the latching mechanism, the return spring allocated to the primary lock must therefore provide a correspondingly high returning force. This returning force is then in turn to be taken into account when configuring the latching mechanism with regard to its force reduction and when configuring the mechanisms providing the triggering force for releasing the locking.